/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup   PIOS_USB_RCTX USB RC Transmitter/Joystick Functions
 * @brief PIOS USB implementation for a HID Joystick
 * @notes      This implements transmitter/joystick emulation over HID reports
 * @{
 *
 * @file       pios_usb_rctx.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_USB_RCTX

#include "pios_usb_rctx_priv.h"

/* STM32 USB Library Definitions */
#include "usb_lib.h"

#define PIOS_USB_RCTX_NUM_CHANNELS 8

enum pios_usb_rctx_dev_magic {
    PIOS_USB_RCTX_DEV_MAGIC = 0xAB98B745,
};

struct pios_usb_rctx_dev {
    enum pios_usb_rctx_dev_magic   magic;
    const struct pios_usb_rctx_cfg *cfg;

    uint32_t lower_id;

    struct {
        uint8_t  id;
        uint16_t vals[PIOS_USB_RCTX_NUM_CHANNELS];
    } __attribute__((packed)) report;
};

static bool PIOS_USB_RCTX_validate(struct pios_usb_rctx_dev *usb_rctx_dev)
{
    return usb_rctx_dev->magic == PIOS_USB_RCTX_DEV_MAGIC;
}

#ifdef PIOS_INCLUDE_FREERTOS
static struct pios_usb_rctx_dev *PIOS_USB_RCTX_alloc(void)
{
    struct pios_usb_rctx_dev *usb_rctx_dev;

    usb_rctx_dev = (struct pios_usb_rctx_dev *)pios_malloc(sizeof(*usb_rctx_dev));
    if (!usb_rctx_dev) {
        return NULL;
    }

    usb_rctx_dev->magic = PIOS_USB_RCTX_DEV_MAGIC;
    return usb_rctx_dev;
}
#else
static struct pios_usb_rctx_dev pios_usb_rctx_devs[PIOS_USB_RCTX_MAX_DEVS];
static uint8_t pios_usb_rctx_num_devs;
static struct pios_usb_rctx_dev *PIOS_USB_RCTX_alloc(void)
{
    struct pios_usb_rctx_dev *usb_rctx_dev;

    if (pios_usb_rctx_num_devs >= PIOS_USB_RCTX_MAX_DEVS) {
        return NULL;
    }

    usb_rctx_dev = &pios_usb_rctx_devs[pios_usb_rctx_num_devs++];
    usb_rctx_dev->magic = PIOS_USB_RCTX_DEV_MAGIC;

    return usb_rctx_dev;
}
#endif /* ifdef PIOS_INCLUDE_FREERTOS */

static void PIOS_USB_RCTX_EP_IN_Callback(void);
static void PIOS_USB_RCTX_SendReport(struct pios_usb_rctx_dev *usb_rctx_dev);

/* Need a better way to pull these in */
extern void(*pEpInt_IN[7]) (void);

int32_t PIOS_USB_RCTX_Init(uint32_t *usbrctx_id, const struct pios_usb_rctx_cfg *cfg, uint32_t lower_id)
{
    PIOS_Assert(usbrctx_id);
    PIOS_Assert(cfg);

    struct pios_usb_rctx_dev *usb_rctx_dev;

    usb_rctx_dev = (struct pios_usb_rctx_dev *)PIOS_USB_RCTX_alloc();
    if (!usb_rctx_dev) {
        goto out_fail;
    }

    /* Bind the configuration to the device instance */
    usb_rctx_dev->cfg = cfg;
    usb_rctx_dev->lower_id = lower_id;

    /* Set the initial report buffer */
    memset(&usb_rctx_dev->report, 0, sizeof(usb_rctx_dev->report));

    pEpInt_IN[cfg->data_tx_ep - 1] = PIOS_USB_RCTX_EP_IN_Callback;

    *usbrctx_id = (uint32_t)usb_rctx_dev;

    return 0;

out_fail:
    return -1;
}

static void PIOS_USB_RCTX_SendReport(struct pios_usb_rctx_dev *usb_rctx_dev)
{
#ifdef PIOS_INCLUDE_FREERTOS
    bool need_yield = false;
#endif /* PIOS_INCLUDE_FREERTOS */

    usb_rctx_dev->report.id = 3; /* FIXME: shouldn't hard-code this report ID */

    UserToPMABufferCopy((uint8_t *)&usb_rctx_dev->report,
                        GetEPTxAddr(usb_rctx_dev->cfg->data_tx_ep),
                        sizeof(usb_rctx_dev->report));

    SetEPTxCount(usb_rctx_dev->cfg->data_tx_ep, sizeof(usb_rctx_dev->report));
    SetEPTxValid(usb_rctx_dev->cfg->data_tx_ep);

#ifdef PIOS_INCLUDE_FREERTOS
    if (need_yield) {
        vPortYield();
    }
#endif /* PIOS_INCLUDE_FREERTOS */
}

static void PIOS_USB_RCTX_EP_IN_Callback(void)
{
    struct pios_usb_rctx_dev *usb_rctx_dev = (struct pios_usb_rctx_dev *)pios_usb_rctx_id;

    bool valid = PIOS_USB_RCTX_validate(usb_rctx_dev);

    PIOS_Assert(valid);

    if (!PIOS_USB_CheckAvailable(usb_rctx_dev->lower_id)) {
        return;
    }

    PIOS_USB_RCTX_SendReport(usb_rctx_dev);
}

void PIOS_USB_RCTX_Update(uint32_t usbrctx_id, const uint16_t channel[], const int16_t channel_min[], const int16_t channel_max[], uint8_t num_channels)
{
    struct pios_usb_rctx_dev *usb_rctx_dev = (struct pios_usb_rctx_dev *)usbrctx_id;

    bool valid = PIOS_USB_RCTX_validate(usb_rctx_dev);

    PIOS_Assert(valid);

    if (!PIOS_USB_CheckAvailable(usb_rctx_dev->lower_id)) {
        return;
    }

    for (uint8_t i = 0;
         i < PIOS_USB_RCTX_NUM_CHANNELS && i < num_channels;
         i++) {
        int16_t min  = channel_min[i];
        int16_t max  = channel_max[i];
        uint16_t val = channel[i];

        if (channel_min[i] > channel_max[i]) {
            /* This channel is reversed, flip min and max */
            min = channel_max[i];
            max = channel_min[i];

            /* and flip val to be an offset from the lower end of the range */
            val = channel_min[i] - channel[i] + channel_max[i];
        }

        /* Scale channel linearly between min and max */
        if (min == max) {
            val = 0;
        } else {
            if (val < min) {
                val = min;
            }
            if (val > max) {
                val = max;
            }

            val = (val - min) * (65535 / (max - min));
        }

        usb_rctx_dev->report.vals[i] = val;
    }

    if (GetEPTxStatus(usb_rctx_dev->cfg->data_tx_ep) == EP_TX_VALID) {
        /* Endpoint is already transmitting */
        return;
    }

    PIOS_USB_RCTX_SendReport(usb_rctx_dev);
}

#endif /* PIOS_INCLUDE_USB_RCTX */
